| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be [vb pp] over a long period | 14 |
|
| 2 | be [vb pp] over a [adj] period | 11 |
|
| 3 | are [vb pp] over a [adj] period | 8 |
|
| 4 | been [vb pp] over a [adj] period | 8 |
|
| 5 | is [vb pp] over a [adj] period | 5 |
|
| 6 | was [vb pp] over a [adj] period | 5 |
|
| 7 | be [vb pp] over a three-year period | 5 |
|
